apache_beam.io.mongodbio module

This module implements IO classes to read and write data on MongoDB.

Read from MongoDB

ReadFromMongoDB is a PTransform that reads from a configured MongoDB source and returns a PCollection of dict representing MongoDB documents. To configure MongoDB source, the URI to connect to MongoDB server, database name, collection name needs to be provided.

Example usage:

pipeline | ReadFromMongoDB(uri='mongodb://localhost:27017',
                           db='testdb',
                           coll='input')

Write to MongoDB:

WriteToMongoDB is a PTransform that writes MongoDB documents to configured sink, and the write is conducted through a mongodb bulk_write of ReplaceOne operations. If the document’s _id field already existed in the MongoDB collection, it results in an overwrite, otherwise, a new document will be inserted.

Example usage:

pipeline | WriteToMongoDB(uri='mongodb://localhost:27017',
                          db='testdb',
                          coll='output',
                          batch_size=10)

No backward compatibility guarantees. Everything in this module is experimental.

class apache_beam.io.mongodbio.ReadFromMongoDB(uri='mongodb://localhost:27017', db=None, coll=None, filter=None, projection=None, extra_client_params=None)[source]

Bases: apache_beam.transforms.ptransform.PTransform

A PTransform to read MongoDB documents into a PCollection.

Initialize a ReadFromMongoDB

Parameters:
  • uri (str) – The MongoDB connection string following the URI format
  • db (str) – The MongoDB database name
  • coll (str) – The MongoDB collection name
  • filter – A bson.SON object specifying elements which must be present for a document to be included in the result set
  • projection – A list of field names that should be returned in the result set or a dict specifying the fields to include or exclude
  • extra_client_params (dict) – Optional MongoClient parameters
Returns:

PTransform
expand(pcoll)[source]
class apache_beam.io.mongodbio.WriteToMongoDB(uri='mongodb://localhost:27017', db=None, coll=None, batch_size=100, extra_client_params=None)[source]

Bases: apache_beam.transforms.ptransform.PTransform

WriteToMongoDB is a PTransform that writes a PCollection of mongodb document to the configured MongoDB server.

In order to make the document writes idempotent so that the bundles are retry-able without creating duplicates, the PTransform added 2 transformations before final write stage: a GenerateId transform and a Reshuffle transform.:

              -----------------------------------------------
Pipeline -->  |GenerateId --> Reshuffle --> WriteToMongoSink|
              -----------------------------------------------
                              (WriteToMongoDB)

The GenerateId transform adds a random and unique*_id* field to the documents if they don’t already have one, it uses the same format as MongoDB default. The Reshuffle transform makes sure that no fusion happens between GenerateId and the final write stage transform,so that the set of documents and their unique IDs are not regenerated if final write step is retried due to a failure. This prevents duplicate writes of the same document with different unique IDs.

Parameters:
  • uri (str) – The MongoDB connection string following the URI format
  • db (str) – The MongoDB database name
  • coll (str) – The MongoDB collection name
  • batch_size (int) – Number of documents per bulk_write to MongoDB, default to 100
  • extra_client_params (dict) –

    Optional MongoClient parameters as keyword arguments
Returns:

PTransform
expand(pcoll)[source]